60 LINN^AN GENERA. 



of colour ; apex obtuse, and placed towards the narrow end 

 of the shell, which is usually ovate. From one to two 

 inches long. Inhabits the shores of Northern Europe. 



Patella Chinensis — The Chinese Patella. Plate III. 

 fig. 6. (Calyptrsea sinensis, Lamarck.) Shell sub-conic, 

 sub-pellucid, and very thin, colour whitish, much compressed, 

 rounded at the margin ; vertex central, terminating in a sub- 

 spiral volution, with usually a number of concave scales. 

 Inside white, glossy, and smooth, with a sub-spiral colu- 

 mella or pillar-lip, extending from nearly the margin to the 

 end, and forming the external sub- volution ; it is broad, flat, 

 and oblique. Found in Helford harbour, Cornwall ; in Sal- 

 comb bay, Devonshire, by Col. Montagu ; and near Dunbar, 

 by Captain Laskey. 



The shells of this genus inhabit the sea, lakes, and rivers. Those of 

 the sea in general adhere to rocks and stones on the shore ; and are 

 so tenacious, that they cannot be removed without great force, unless 

 taken by surprise. Those inhabiting fresh water are generally found 

 attached to stones or aquatic plants. The Patellae are called Limpets 

 in Britain. 



w Chamber. 



Genus 33.— DENTALIUM. 



Animal a Terebella; shell univalve, tubular, straight, or 

 slightly curved, with the cavity undivided, and open at both 

 ends. 



Dentalium Entalis. — The Tooth Dentalium. Plate 

 IX. fig. 33. White or yellowish, slightly curved, and taper- 

 ing to a fine point; slightly striated. One and a half "inch 

 long. Inhabits the British seas. 



The shells of this genus are only found in the ocean. They are soli- 

 tary, and lie in the mud, in an oblique or perpendicular position. 



Genus 34 SERPULA. 



Animal a Terebella; shell univalve, tubular, generally 

 adhering to other substances ; often separated internally by 

 divisions at uncertain distances. 



Serpula vermicularis The Worm-like Serpula. Plate 



IX. fig. 34. White, cylindrical, tapering, and variously curved 



